Concepts3

Double Counting

Double counting is the strategy of counting the same quantity in two different ways to derive an equality or an efficient algorithm.

#double counting#contribution technique#handshake lemma+12

⚙️AlgorithmIntermediate

Contribution Technique

The contribution technique flips perspective: compute how much each element contributes to the total, then sum these contributions.

#contribution technique#monotonic stack#sum of subarray minimums+12

⚙️AlgorithmAdvanced

DP with Expected Value

Dynamic programming with expected value solves problems where each state transitions randomly and we seek the expected cost, time, or steps to reach a goal.

#expected value dp#linearity of expectation#indicator variables+11